Hi. I'm new here. Today I had a problem with UUID and everything is ok now..except one thing. When i had that problem, firefox was opened and now, when I want to open it a window "Start new session, Restore session" is showing, but when I choose first or second option nothing happens. When I try again it shows again. Soo please, help me guys. I have Linux Mint "Cassandra".

Try starting it from a terminal to see if it will show any errors to help troubleshoot. It sounds like it is stuck in a loop. It wants confirmation, but won't let you give any Just open a terminal and run

That is a xorg error. It may or may not be related. I would try deleting your firefox profile in your ~/.mozilla folder. Backup your bookmarks and other stuff you want to keep. Then try restarting Firefox. Sometimes your Firefox profile gets corrupted.

"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke